1. Field of The Invention
In one aspect this invention relates to fire control systems. More particularly, this invention relates to the activation systems used to start and control the flow of fire extinguishant from a fire control system. In yet a further aspect this invention relates to a control system which will activate the extinguisher when the sensor which normally is used to activate the system is suddenly severed from the rest of the system.
2. Description of the Art
The modern battlefield presents a complex interplay between increasingly sophisticated armor and the antiarmor rounds designed to defeat the armor. No where is this interplay more pronounced than in the armored vehicles. The penetration of an antiarmor round into the interior passenger or engine compartment of the armored vehicle can rupture a fuel cell or other explosive material and will cause a fire which will quickly destroy the personnel and the vehicle. The fear of being trapped inside the burning vehicle is a great deterrent to crew effectiveness. The violent threat represents a significant psychological barrier to effective crew performance. It is therefore imperative to have a fire suppression system on board the vehicle which can react promptly to the incursion of a projectile which causes or can cause a fire. It is also important to limit the amount of damage done to a vehicle when hit in order to reduce the damage done to the expensive vehicles thereby minimizing the loss of material in combat conditions.
Systems for surpressing a fire in the passenger and engine compartments generally comprise a supply of halogenated hydrocarbon such as bromotrifluoromethane, commonly known as Halon-1301, under pressure (e.g. 750 psi) which is contained in one or more bottles in the passenger compartment or other vehicle area sought to be protected. The bottles are connected to a plurality of nozzles which are placed to deliver the Halon to, various parts of the compartment being protected. The connection between bottles and nozzles being within the skill of the art will not be discussed in detail. One or more sensors are placed within the cabin being protected to sense the presence of the type of fire to be surpressed. The sensors are chosen to be sensitive to the radiation given off by fires and are generally placed with overlapping coverage so no volume of the compartment is left unmonitored. In response to a fire the sensors will generate a signal which will go to a centralized control unit and the control unit will activate the system to release Halon to the areas which are on fire. The pressurized bottles of Halon are equipped with fast acting valves which are activated by the control unit and which allow rapid release of the Halon when needed. In a combat situation, it is a goal that the Halon be dispensed into the fire within 100 milliseconds after the onset of the fire. The systems installed in combat vehicles act automatically and without human intervention because of the speed with which the fire extinguishant must be dispensed. There are many different types of halogenated hydrocarbon supply systems available which can be mounted on or in an armored vehicle. These systems have sufficient fire arresting power to stop most fires promptly. Of course, it is necessary that the fluorocarbon be dispensed promptly when a threat in the passenger compartment is sensed.
Various sensing systems have been proposed to signal the presence of a fire in the passenger compartment and send a signal to the remainder of the system to start the flow of extinguishing fluid. Such sensors have been developed to a high degree and provide very fast response. Armored vehicles are subject to catastrophic failure modes when they are struck by such rounds and there exists a real possibility that the sensing system will be damaged. A damaged system which fails to extinguish a fire represents a real hazard.
It is an object of the invention to provide a system where the destruction of the sensing circuitry which would normally trigger the system will itself trigger the system to prevent the destruction of the vehicle and its personnel.